From: "Zhu Zihao" <all_but_last@163.com>
To: emacs-devel@gnu.org
Subject: Re:New lisp library -- cell.el
Date: Fri, 28 Feb 2020 16:51:58 +0800 (CST) [thread overview]
Message-ID: <5ba4e906.6dfb.1708afecaf2.Coremail.all_but_last@163.com> (raw)
In-Reply-To: <b3cbce2.31e2.1708a74bc6f.Coremail.all_but_last@163.com>
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I can't send my file for unknown reason. So I post it to Github
https://github.com/cireu/emacs-cell
At 2020-02-28 14:21:11, "Zhu Zihao" <all_but_last@163.com> wrote:
In last month I sent an email to request for some comments on weak reference facilities in Emacs. Now I create a new lisp library -- cell.el, which implemented weak reference in Elisp using weak hash table and some more util.
There are 3 kinds of cell in cell.el
- Option :: Giving "existence" information for a value, Like Maybe type in Haskell or Optional type in Java.
- Box :: Like a single element vector, create a mutable storage.
- Weak :: Weak reference I mentioned above.
IMO, these can help user to build Elisp application in more convenient way.
For a simple example.
(plist-get '(:key nil) :key) ; => nil
(plist-get '(:key nil) :val) ;=> nil
By using Option Cell, we can differentiate these two status.
(defun clear-plist-get (plist key)
(pcase (plist-member plist key)
(`(,_k ,v)
(cell-option-some v))
(_
(cell-option-none))))
(let ((plist '(:key nil)))
(plist-get plist :key) ;=> nil
(plist-get plist :val) ;=> nil
(clear-plist-get plist :key) ;=> Some(nil)
(clear-plist-get plist :val) ;=> None
)
I don't want to break the behaviour of plist-get, just a example to show the power of Option Cell. And there are detailed description in ;;; Commentary section.
Would you consider this to be included in Emacs core, or publish it on GNU ELPA?
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next prev parent reply other threads:[~2020-02-28 8:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-28 6:21 New lisp library -- cell.el Zhu Zihao
2020-02-28 8:51 ` Zhu Zihao [this message]
2020-02-28 15:43 ` Stefan Monnier
2020-02-28 16:51 ` Zhu Zihao
2020-02-29 3:30 ` Stefan Monnier
2020-02-29 6:48 ` Zhu Zihao
2020-02-29 14:09 ` Stefan Monnier
2020-03-01 7:43 ` Zhu Zihao
2020-03-05 15:52 ` Stefan Monnier
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